Method of fabricating a doublewall container



y 22, 1952 E. MCK. BEEKMAN 2,604,426

METHOD OF FABRICATING A DOUBLE-WALL CONTAINER Filed Sept. 1, 1950 Has'IIII Patented July 22 1952 ?U ;"IT D-. A E T mar- METHOD OF FABRICATINGA DOUBLE- WALL GONTAINER Emile McK. Beekman, Sea Bright, N. J assignorto the United States of America as represented by the Secretary of theArmy,

7 Application September 1, 1950, Serial No. 182,697

4 Claims. (01.154-83) '(Granted undertheact of'March ii; 1883, as Iamende'd Apr il 30, 1928; 37 0. G. 757) l The invention described hereinmay be manufactured andlused' by orfor the Government; for governmentalpurposes, withoutthe payment of any royalty thereon. V

This invention relates to an improved method of fabricating adouble-wall container.

'Double-Wallcontainers of various kinds have been'used for. the casingsorcabinets of apparatus and articles, and for storing or transportingthe same. In thehan'dling or useof storage batteries, for example, thesize and weightof the same, as well as the mechanicalshocks. to whichthey aresometimessubjected continuously under extremely unfavorabletemperature conditions or sudden changes in temperature, it'becomesimportant to provide a suitable casing or container whichwill stand upunder the rough usage and diflicult;conditions thereby toprotect theencased battery against damage which otherwise would result.

vWith the foregoing in mind, it is one of the objects of theinvention toprovidean improved method of fabricating a double-wall container wherebythe four double-walls of a square or rectangular, container, forexample, can be formed simultaneouslyand by the use of. relativelysimple techniques, and in such manner that the finished article willhave the ruggedness'and the insulating properties'required to stand upunder severe operating. conditions, thereby to protect; the con-.

tents against destruction or substantial damage Fig. 1 'is an isometricview of the mold parts used in carrying out the improved fabricatingmethod in accordance with the invention;

Fig. 2 is a fragmentary, elevational view illustrative of one of themethod steps;

I Fig. 3 15a view similar to Fig. 2 but partly broken away; andillustrative of a succeeding step in the improved method;

Fig. 4 is an elevational view illustrative of the technique employed incarrying out the method step to followthatshown in Fig.3;

Figs. 5 and 6 areplan views explanatory of the fabrication technique.employed after completion of thestepshown in Fig.4;

trative of the method step to follow that shown in Fig. 6; I

Fig. v8 is a plan view, partly in section fof a container fabricated inaccordance with the invention, the section being taken on the line 8-98in Fig. 9; I Fig. 9 is a frontyelevational view, partly in section, ofthe container shown inFig. 8, the section being'ta'ken on the line 99 inFig. 10: and

Fig. 10 is an elevational view, partly in section, of the containershown in Fig. 8, the section being taken on the line vl0ll'l in Fig. 9.

For the purpose of. simplification, the mold parts used in carrying outthe improved fabrication method have been shown isometrically in Fig. 1,out of association with any other parts, and in the relative respectivepositions they have after the final assembly or fabrication step. Theseparts shall be identified as the lower inner mold Hi, the upper innermold I l, the outer side molds I2 and (4, respectively, and the outerend molds l5 and [6, respectively.

Figs. 8, 9 and 10 are illustrative of a rectangular, double-wallcontainer made in accordance with the improved fabrication methodclaimed herein. The container consists of the inner side walls Ila andllb, the inner end walls lie and lid, the outer side walls l2a and I 4a,the outer end walls I51: and [6a, and the base Illa. In the claims, theterm base is used in the broad sense and is intended to refer toan'endlwall which might be considered 'as either the top or the bottomof the container, depending upon the position of the latter or thespecific use to which it is put. Ateach of the four corners the innerand outer walls are connected andreenforced by the longitudinallydisposed ribs or webs l1, l8, l9, and 20.

In carrying out the first step in the improved fabrication method, toform the bottom I00. of the container, several layers 2| of pliable,impregnated material are placed upon the lower inner mold l0, after whichthe upper inner mold H is placed upon' these layers and lined upvertically with mold Ill, as shown in Fig.2.

The material vused for'the layers 2|. and in .the other method stepshereinafter explained, maybe sheets of paper or wood; sawdust, lignin,

rag, vegetable fibre, animal hair, glass mat, or

.anyfc'ombin'ationj of these pressed into a mat;

cotton, linen, glass, or jsynthetic resin fabric, or any combinationofthese; natural or synthetic:

or resin-retentive material is first impregnated sembly shown in Fig. 6.for reenforcement or additional strength at the juncture of adjacentouter molds.

The assembly in Fig. 651s now placed upon the bed-plate 23and.wrapped,-;as'inFig-g4, with resinimpregnated, strip material 21, toform the outer side Walls [2a and Ma and the outer end walls with asuitable resin such as a thermosetting low-pressure or contact-pressureresin, or a then moplastic resin.

The dimensions of layers 2 l are such that along each of the four edges,the material protrudes or extends beyond molds V which may be aboutthree inches; The layers I form the bottom Ilia of the completecontainer- I0 and H a distanceshown in Figs. 8, 9 and 10, and the numberused 7 d I suflicient' taper, and also to cover them with celis inaccordance with what the thickness" or ing edges 2I of the top half oflayers 2! are folded up,- asshown in Figs'Zand 3, against the respectiveside andend faces of the upper inner mold H.1 In like mannen theprotrudingedges 2| b of the'bottom'hali of" layers 2| are folded down"against the respective side and end faces of the lower inner mold II),as shown. For the purpose of reenforcement or additional strength at thejuncture of the, inner molds wand I'I, perforated sheets or strips 22 ofthe impregnated material may be wrappedabout the assembly as shown inFig. 3. I V p In carrying outthenext step inthe improved fabricationmethodgthe assembly in Fig. 3 is placed in a 'suitable jig as shown inFig.4. This may comprise a horizontally-disposed table or bedplatensupported for rotation, and adjustable structure designated generallyby the reference numeral 24 and providing an upper bearing to supportthe assembly for. rotation with the bed-plate 23, 'abouta'verticalaxis.An end of a strip 25 of the resin-impregnated material is'stuck orotherwise secured to one of the side or end faces of inner mold H, atthe top edge thereof the bed-plate 23 is rotated as indicated by thearrows; and the strip of material is guided 'downwardlyuntil the innermolds are. completely wrappedabout'with a layer of the strip-material.The latter is then guided upwardly until the inner=moldsare againcompletely wrapped about with a second layerlof the strip-material. Thisioperation forms the inner walls I la, Mb, 1 lo and lid of' tlie'complete1container shown in Figs. 8, '9 andlO, and isrepeateduntilsufficient layersof. the materialhave been wrapped about inner molds H3and Ifl'to give the desired thick;

ness or gauge for these inner walls. Only the top surface'of' the upperinner mold H and the bottom surface of the lower inner: mold 10, nowremain uncovered.

' Sheets I2a, 14c, l5a'and'ita oi resinei npregnated material, equal inheight to the outer molds I2, l4, l5 and I5, are now placed against theinner faces ofthe lattenras' shown in Fig. 5, and their edges, foldeddown over the longitudinal edgesof the outer molds' These sheets add tothe thickness 'of' the inner'walls' Ha, I lb, He and ljd of the completecontainer, and the folded edges form the reenforcing WebSi'l, l8, l9 and20. The outer molds, with the sheets of resin-impregnated materialapplied thereto as shown in.Fig.5, are now fitted about the; wrappedinner-mold assembly which resulted jfromjthe step shown in Fig; 4. Thisresults in the combination shown in Fig. .6. Perforated strips. 26 ofresin-impregnated material are placed aroundthe corners of the as- 7gauge of the bottom lflapis to be. The pretend:

I Ja and lea. This wrapping step is continued,

'35 in Fig. 4; until the outer walls have the desired ture, pressure andcuring time depending upon the typeof ir'n'pregnating resin used, and,then themolds are removed. To facilitate removal of the molds it isproposed to form them with a lophaneor' a'lubricanti Any material whichis sufi'iciently rigid to withstand the molding temperature andpressure, may be used for the molds, and-thee'dg'es of the latter arerounded and hooks may be embedded in the material to facilitate re movalfrom the finished piece. i

After removal of the inner and outer'molds, the space betweenthe doublewalls, as well as the space formerly occupied by the lower inner moldIt], may be'filled with a suitable insulating ma terial- 'A cover (notshown) is fitted across the bottom'o'f the unit't'oprovide an insulated,doublewall structure for 'the bottom. 2 i Instead ofapplying sheetmaterial to the outer molds 'as in Fig. 5',the latter may be'wrapped-imdividually with resin-impregnated" strip-mate'- rial, as'in Figs. 4 and7. Also; insteadofi'us'ing strip-material-as shown in Figsl l and .7,the two respective assemblies may be wrapped with resi'nimpregnatedfsheet-material, the width of .the sheets being equal to theheight 'of these assemblies, and the sheets used in suificient number togive the desired thickness or gauge-to the walls. Double-wallcontainersof a wide varietyof shapes and sizes may be made in accordance with theimproved fabrication method by constructing the inner andouter moldpartsa'ccordingly, to meet or comply with the particular specifications.As a further. modification in the. improved fab rication method; forsome double-wall; containers it is proposed'to use outer molds formed-orconstructed as a honeycorhb, and to leave these in the finished unit asintegral parts-thereof;

Forthe'purposeof clearer illustration 'of an embodiment 'ofpth'einvention, the thickness or gauge of the sheets and strips ofresin-imprege nated material has been shown on-an exaggerated scale inthe drawing.

' ered to reside in: an improved method for r'fabricating a double-wallcontainer such as is'shown in Figs. 8, 9 and.10;wherein an'inner mold,such as l B or i l, is first set up to'fix the shape and size ofcontainer desired; wherein pliable material, either. in strip or sheetform. is then applied to the inner mold; to'substantially cover thelatter; wherein parts constituting an outer-mold assembly, such as the.parts I2, 4', i5 and iii, are then applied to the covered inner: mold.as 'showii' in Fig.- 6; wherein an additional'supply ofithel pli ablematerial is then applied about the outermold assembly to form thedouble-wall construction; and wherein this combination'is then treatedto cause the double-wallconstruction of the pliable material to becomerigid; 'l l For .examplesof suitable resins'sucn as a thermcsettinglow-pressure orc'ontract-pressure-resin or such as a thermoplastic resinwhich might be used in carrying out the present invention, and fordetails concerning operating techniques in the processing of such resinsand concerning, particularly, respective ranges of temperature and ofpressure usable in processing resin-impregnated materials in accordancewith the present invention, reference is made to the prior art, anexample of which being the book by Herbert R. Simonds and M. H. Bigelowentitled The New Plastics, published May 1945 by D. Van NostrandCompany, Inc., 250 Fourth Avenue, New York, N. Y.

It will be apparent to those skilled in the art that various changes ormodifications, other than those disclosed herein, are possible withoutdeparting from the spirit of the invention, or the scope of the claims.

The invention claimed is:

, 1. In the art of fabricating a double-wall container, the method stepswhich include setting up lower and upper inner-mold parts to fix theshape and size of the container desired; resin-impregnating pliable andabsorbent material; interposing between said parts some of said materialto form the bottom of said container; wrapping some of said materialabout said parts and about and in contact with the edges of said bottommaterial to form inner walls for said container; applying, to thewrapped inner-mold parts, parts constituting an outer-mold assembly;wrapping some of the pliable and impregnated material about saidouter-mold assembly to form with said inner walls a double-wallconstruction; subjecting the assembly aforesaid to conditions oftemperature and pressure respectively appropriate for curing the resinand for a period of time sufflcient for the resin-impregnated materialto become relatively rigid; and removing said innermold parts and saidouter-mold parts out of association with the relatively rigid wrappingsto leave per se the double-wall container of the shape and size desired.

2. In the art of fabricating a double-Wall container, the method stepswhich include resinimpregnating pliable and absorbent material, shapingand supporting some of said impregnated material to constitute a basefor said container, shaping and supporting some of said impregnatedmaterial about and in contact with the edges of said base material toconstitute the inner-wall structure for said double-wall container,shaping and supporting some of said impregnated material about and inspaced relation with respect to said inner-wall material to constitutethe outer-wall structure for said double-wall container; and subjectingthe assembly comprising said base material and said inner-wall materialand said outer-wall material to temperature and pressure conditionsrespectively appropriate for curing the resin and maintained for aperiod of time sufiicient to cause said assembly to become a unitary,double-wall, rigid container of the character described.

3. In the art of fabricating a double-wall container, the method stepswhich include resin-impregnating pliable and absorbent material, shapingand supporting some of said impregnated material to constitute a basefor said container, shaping and supporting some of said impregnatedmaterial about and in contact with the edges of said base material toconstitute the inner-wall structure for said double-wall container,shaping and supporting some of said impregnated material about and inspaced relation with respect to said inner-wall material to constitutethe outerwall structure for said double-wall container, shaping andsupporting some of said impregnated material to extend longitudinally ofthe container and between and in contact with the adjacent faces of thedouble-wall structure; and subjecting the assembly comprising saidlastnamed material and said base material and said inner-wall materialand said outer-wall material to temperature and pressure conditionsrespectively appropriate for curing the resin and maintained for aperiod of time suificient to cause said assembly to become a unitary,double-wall, rigid container of the character described.

4. In the art of fabricating a substantially rectangular, double-wallcontainer having a reenforcing web between the double-wall structure ateach of the four corners thereof; the method steps which includeresin-impregnating pliable and absorbent material, shaping andsupporting some of said impregnated material to constitute a base forsaid container, shaping and supporting some of said impregnated materialabout and in contact with the edges of said base material to constitutethe inner-wall structure for said double-wall container, shaping andsupporting some of said impregnated material about and in spacedrelation with respect to said inner-wall material to constitute theouter-wall structure for said double-wall container, shaping andsupporting some of said impregnated material to extend longitudinally ofthe container and between and in contact with the adjacent faces of thedouble-wall structure at each of said four corners; and subjecting theassembly comprising said last-named material and said base material andsaid inner-wall material and said outerwall material to temperature andpressure conditions respectively appropriate for curing the resin andmaintained for a period of time sufficient to cause said assembly tobecome a unitary, double-wall, rigid container of the characterdescribed.

EMILE MCK. BEEKMAN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,393,541 Kemp Oct. 11, 19211,520,996 Bastian Dec. 30, 1924 2,340,209 Skolnik Jan. 25, 19442,445,290 Gonda July 13, 1948

2. IN THE ART OF FABRICATING A DOUBLE-WALL CONTAINER, THE METHOD STEPSWHICH INCLUDE RESINIMPREGNATING PLIABLE AND ABSORBENT MATERIAL, SHAPINGAND SUPPORTING SOME OF SAID IMPREGNATED MATERIAL TO CONSTITUTE A BASEFOR SAID CONTAINER, SHAPING AND SUPPORTING SOME OF SAID IMPREGNATEDMATERIAL ABOUT AND IN CONTACT WITH THE EDGES OF SAID BASE MATERIAL TOCONSTITUTE THE INNER-WALL STRUCTURE FOR SAID DOUBLE-WALL CONTAINER,SHAPING AND SUPPORTING SOME OF SAID IMPREGNATED MATERIAL ABOUT AND INSPACED RELATION WITH RESPECT TO SAID INNER-WALL MATERIAL TO CONSTITUTETHE OUTER-WALL STRUCTURE FOR SAID DOUBLE-WALL CONTAINER; AND SUBJECTINGTHE ASSEMBLY COMPRISING SAID BASE MATERIAL AND SAID INNER-WALL MATERIALAND SAID OUTER-WALL MATERIAL TO TEMPERATURE AND PRESSURE CONDITIONSRESPECTIVELY APPROPRIATE FOR CURING THE RESIN AND MAINTAINED FOR APERIOD OF TIME SUFFICIENT TO CAUSE SAID ASSEMBLY TO BECOME A UNITARY,DOUBLE-WALL, RIGID CONTAINER OF THE CHARACTER DESCRIBED.